This invention relates generally to polymer compositions, and more particularly to sulfonated polyarylenethioethersulfone polymer and copolymer compositions.
Over the last decade, several new proton conducting polymer electrolyte membranes have emerged. The new polymers in fuel cell applications are based mostly on hydrocarbon structures for the polymer backbone. These new membrane concepts include fluorinated, partially fluorinated, composite, and aromatic polymer membranes.
Due to their chemical stability, high degree of proton conductivity, and mechanical properties, perfluorinated polymer electrolytes available from companies such as DuPont (Nafion®), Asahi Chemical (Aciplex®), and Asahi Glass (Flemion®), and membranes available from Dow Chemical, are some of the most promising proton exchange membranes (PEMs). They serve as the benchmark for future development of polymer electrolyte fuel cells.
While perfluorinated polymer electrolytes have satisfactory properties for fuel cell membrane applications, especially at temperatures up to 80° C., they have low proton conductivities at temperatures over about 80° C., and at low humidity. In addition, perfluorinated polymer electrolytes are expensive.